Trend Micro InterScan Gateway Security Appliance M-Series ...

Trend Micro InterScan Gateway Security Appliance M-Series Administrator’s Guide
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FIGURE 14-3. Compression ratio
Action on unscanned files:
Unscanned or unscannable files include files that are password protected.
Handling Large Files
For larger files, a trade-off must be made between the user’s experience and expectations
and maintaining security. The nature of virus scanning requires doubling the
download time (that is, the time to transfer the entire file to InterScan Gateway Security
Appliance, scan the file, and then transfer the entire file to the client) for large
files.
In some environments, the doubling of download time may not be acceptable. There
are other factors such as network speed and server capability that must be considered.